Insert for mattress

ABSTRACT

A support layer for a mattress and a corresponding manufacturing process are provided, comprising a first surface and a second surface, the second surface being disposed opposite the first surface. The first surface comprises a plurality of protrusions extending laterally to a length of the support layer, the protrusions defining a plurality of cavities extending laterally to the length of the support layer. The shape of the protrusions matches the shape of the cavities when the support layer is in a substantially planar state. The protrusions and cavities each have a base portion and a head portion, the head portion defining an undercut. Further, a mattress comprising at least one support layer is provided.

TECHNICAL FIELD

The present invention relates to a support layer for a mattress for supporting a body.

BACKGROUND ART

Mattresses are used, for example, for supporting a body of a user and typically contain one or more layers made of latex or polyurethane. The layers have certain properties (e.g. geometry, density, thickness), defining their elasticity, flexibility, stiffness, and other parameters relevant for the use in a mattress.

Generally, a mattress can comprise an the inner core made of foamed flexible material, whereas the inner core typically comprises one or more layers of the material. Further, the mattress can comprise an external textile cover embedding all the internal layers, and upper and lower padding layers made of a material having specific properties with respect to heat insulation, moisture absorption, etc. Example materials for the textile cover and padding layers include cotton, wool, linen, silk, and camel-hair.

The inner (or core) layers are typically monolithic items with a plate-like conformation and a parallelepiped extension. A mattress has an upper surface to support a user's body and a lower surface adopted to rest on a bed frame or similar device. The layers can be manufactured using a raw material (e.g. latex or polyurethane) converted from a liquid state to a foam-like state and successively converted to a solid state by vulcanization.

By virtue of the particular elastic properties of the mattress material, the latter conforms in shape with the user's shape and weight. In this way, the user's prominent and heavy body parts sink into the upper surface of the mattress in an attempt to keep the user's backbone in a preferred posture.

It is desirable to modulate the elastic properties of the mattress, for example the stiffness of specific portions, in order to have a higher grade of support (e.g. higher stiffness) in some areas and a lower grade of support (e.g. higher flexibility or softness) in other areas. In this way, a mattress can be designed to optimally support a user's body in particular situations (e.g., while laying down or sitting on the edge of the bed).

EP 1 723 878 A1 discloses a mattress core made from foamed plastics that has running lengthwise or crosswise cavities, which pass through the mattress core parallel to its top and bottom sides. Further, ventilation channels link up with ventilation ducts and the cavities. The mattress core has a center layer and two covering layers each consisting of strips with a clearance from each other.

DE 103 39 555 A1 discloses a foam mattress that has three layers, which are held together by interlocking ribs and grooves. Upper and lower layers as well as upper and lower sides of the central layer have different flexibilities.

DE 88 07194 U1 discloses a decubitus support layer, in particular a mattress, made from foamed material. A foam plate having a wave-shaped upper surface containing lengthwise wave crests and troughs is provided, on which block-shaped bars, extending over the entire width of the foam plate, can be placed in a manner transversal to the waves.

SUMMARY OF INVENTION

According to the invention, a support layer for a mattress is provided, comprising a first surface and a second surface, the second surface being disposed opposite the first surface. The first surface comprises a plurality of protrusions extending laterally to a length of the support layer, the protrusions defining a plurality of cavities extending laterally to the length of the support layer. The shape of the protrusions matches the shape of the cavities when the support layer is in a substantially planar state. The protrusions and cavities each have a base portion and a head portion, the head portion defining an undercut.

In one aspect, the base portion has a first width and the head portion has a second width, the first width being less than the second width. The protrusions and cavities can be symmetrical with respect to a vertical plane extending through the corresponding base portion, the vertical plane extending laterally to the length of the support layer and being substantially perpendicular thereto. The head portion can be substantially flat. The protrusions and cavities can have a T-shape or an L-shape.

In another aspect, the shape of the protrusions is configured to provide, upon deformation of the support layer along its length, a first stiffness when adjacent protrusions to not contact each other and a second stiffness when adjacent protrusions do contact each other. The first stiffness can be less than the second stiffness. The support layer can be made from a flexible material. The support layer can be made from a material selected from the group consisting of polyurethane and latex.

In another aspect, the plurality of protrusions and cavities are comprised in the first and second surfaces. The protrusions and cavities in the first surface can have a size different from the protrusions and cavities in the second surface.

In another aspect, the support layer is symmetrical with respect to a mid plane extending through the support layer, the mid plane being substantially parallel to the support layer.

In another aspect, the second surface can be substantially flat.

In another aspect, the support layer for a mattress comprises an upper surface and a lower surface, the lower surface being disposed opposite the upper surface. The upper and lower surfaces comprise a plurality of protrusions extending laterally with respect to a length of the support layer, the protrusions defining a plurality of cavities extending laterally with respect to the length of the support layer. The protrusions and cavities each have a respective base portion and a respective head portion, the respective head portions being flat and defining an undercut, the protrusions having a T-shape, and wherein the support layer is made from a flexible material.

In another aspect, the shape of the protrusions matches the shape of the cavities when the support layer is in a substantially planar state.

Further according to the invention, a mattress is provided comprising at least one support layer as described above.

In one aspect, the mattress comprises a lateral insert, the lateral insert comprising protrusions and cavities matching those of the support layer, the lateral insert extending along substantially a width of the support layer and being configured to increase a stiffness of the support layer in an area interested by the lateral insert.

In another aspect, the mattress additionally or alternatively comprises a longitudinal insert, the longitudinal insert comprising protrusions and cavities matching those of the support layer, the longitudinal insert extending along substantially the length of the support layer and being configured to increase a stiffness of the support layer in an area interested by the longitudinal insert.

In an independent aspect, a mattress comprises at least one support layer according as described above, whereas the support layer is positioned between a superjacent layer and a subjacent layer, the superjacent layer having a substantially flat bottom surface and the subjacent layer having a substantially flat top surface, and whereas the support layer is non-planar along its length. The support layer can be curved along its length and straight along its width. The bottom surface of the superjacent layer and/or the top surface of the subjacent layer can be in contact with the support layer.

In another aspect, the mattress can further comprise an upper padding layer and/or a lower padding layer, the upper and lower padding layers preferably comprising cotton, wool, linen, silk, camel-hair, or combinations thereof.

In another aspect, the mattress can further comprise an external cover, the external cover preferably being a textile cover enclosing the entire mattress and layers comprised therein.

Advantages of the support layer and the mattress include that the individual properties of the mattress can be configured by modifying the properties of the support layer(s) and/or by providing the support layer(s) with one or more inserts. In this manner, individual areas of the mattress can be designed to have, for example, a higher stiffness, while other areas of the mattress can be designed to have a lower stiffness. In this way, the supporting characteristics of the mattress can be individually modified in order to optimize specific purposes.

Further a manufacturing process for the support layer as described above is provided, comprising the steps of preparing a pre-product comprising at least one of polyurethane and latex, cutting the support layer from the pre-product such that the protrusions in the support layer form corresponding cavities in the pre-product, and separating the support layer from the pre-product. Cutting the support layer from the pre-product can form a cut that is substantially straight in a direction lateral to the length of the support layer.

In another aspect, the manufacturing process can further comprise the steps of cutting a further support layer from the pre-product such that the protrusions in the support layer form corresponding cavities in the pre-product, and separating the further support layer from the pre-product.

In an alternative aspect, the manufacturing process can further comprise the steps of cutting a further support layer from the pre-product forming a cut between the further support layer and the pre-product, the cut being substantially planar, and separating the further support layer from the pre-product.

Advantages of the manufacturing process include that there is no need for disposing of any clippings or other waste material, because the cutting is performed in a manner in which no material has to be cut from any of the components. Neither the initial pre-product, nor any of the resulting intermediate or final products comprise portions that have to be cut away and be disposed of.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 shows an isometric view of a first embodiment of a support layer having T-shaped protrusions and cavities;

FIG. 1 a shows an enlarged view of a portion of the support layer shown in FIG. 1, the portion being marked by a circle in FIG. 1;

FIG. 2 shows an isometric view of a second embodiment of a support layer;

FIG. 3 shows an isometric view of a third embodiment of a support layer;

FIG. 4 shows an isometric view of a forth embodiment of a support layer having L-shaped protrusions and cavities;

FIG. 5 illustrates a manufacturing step of a support layer such as shown in FIG. 2;

FIG. 6 shows a layered structure for a mattress comprising a support layer such as shown in FIG. 1;

FIG. 7 shows a layered structure for a mattress comprising a support layer such as shown in FIG. 1, the support layer being in a non-planar along its length;

FIG. 8 shows a layered structure for a mattress comprising a support layer such as shown in FIG. 2, comprising additional layers;

FIG. 9 shows an alternative layered structure for a mattress comprising a support layer such as shown in FIG. 2, where the support layer and additional layers are integrally formed;

FIG. 10 a shows a support layer such as shown in FIG. 1 comprising a longitudinal insert;

FIG. 10 b shows a support layer such as shown in FIG. 1 comprising a lateral insert; and

FIG. 11 shows a support layer such as shown in FIG. 1 comprising two longitudinal inserts defining a lateral margin.

DETAILED DESCRIPTION

FIG. 1 shows an isometric view of a first embodiment of a support layer 1 having T-shaped protrusions 3 and cavities 4. In general, the support layer 1 has a length l and a width w, the length l being greater than the width w. The support layer further comprises a base section 2, from which the protrusions 3 extend outwardly, thereby defining the cavities 4. The protrusions 3 and the cavities 4 extend laterally with respect to the length l of the support layer 1. The base section 2 is substantially planar, i.e. it provides a substantially flat and even body.

In the first embodiment, protrusions 3 and cavities 4 are located on both the upper and the lower surface of the support layer 1. Alternatively, protrusions 3 and cavities 4 can be present in only the upper or lower surface of the support layer 1, in which case the surface located opposite the protrusions 3 and cavities 4 may be substantially flat.

FIG. 1 a shows an enlarged view of a portion of the support layer shown in FIG. 1, the portion being marked by a circle in FIG. 1. The protrusions 3 are integrally formed with a surface of the support layer 1 and have substantially a T-shape. The protrusions 3 are formed side by side each other in a manner defining a cavity 4 between two adjacent protrusions 3 having a (reversed) T-shape identical to that of the protrusions 3. Thus, if turned upside down, the protrusions 3 would exactly fit the cavities 4. In other words, two identical support layers 1 having protrusions 3 and cavities 4 could be arranged against one another such that the protrusions of one support layer would accurately fit the cavities in the other support layer, and vice versa.

The protrusions 3 have a head portion 3 a and a base portion 3 b, the base portion 3 b connecting the head portion 3 a to the base section 2 of the support layer 1. The cavities 4 have a head portion 4 a and a base portion 4 b, defining a space between two adjacent protrusions 3. The head portion 4 a of a cavity 4 is located between the base portions 3 b of two adjacent protrusions 3 and the base portion 4 b of a cavity 4 is located between two head portions 3 a of adjacent protrusions 3.

The support layer 1 has a first thickness t₁ that denotes the thickness of the base section 2 (thickness t₁ is generally constant along width and/or along length of the support layer) and a second thickness t₂ that denotes an overall thickness of the support layer including protrusions extending from the upper and/or lower surfaces of the base section 2 of the support layer 1 (thickness t₂ is generally constant along width and/or along length of the support layer). The thickness t₁ of the base section 2 (i.e. the first thickness) can be smaller or greater than the overall thickness minus the thickness of the base section (t₂−t₁) of the support layer 1 (i.e. the second minus first thickness). Depending on the desired characteristics (e.g., stiffness, flexibility), the thicknesses t₁ and/or t₂ can be varied independently and/or with respect to each other.

Moreover the height of the protrusions on one side may be different from the height of the protrusions on the other side of the insert.

In general the height of protrusions 3 and the span of the head portion 3 a of the protrusions on a same side of the insert are configured to create a direct contact between respective head portions 3 a of consecutive protrusions 3 upon bending of the mattress insert. In other terms, in case of bending the insert, consecutive head portions 3 a will touch one another in correspondence of faced lateral sides of the same head portions 3 a.

FIG. 2 shows an isometric view of a second embodiment of a support layer 1. This embodiment illustrates a support layer 1 having protrusions 3 and cavities 4 only on one surface. The protrusions 3 and cavities 4 can be located on either surface, for example on the lower surface or, as shown in FIG. 2, on the upper surface of the support layer 1. The respective opposite surface can be substantially flat, as shown with the lower surface of support layer 1 as shown in FIG. 2. Support layer 1 as shown in FIG. 2 also comprises a base section 2 that is substantially flat.

FIG. 3 shows an isometric view of a third embodiment of a support layer 1. This embodiment illustrates a support layer 1 having protrusions 3 and cavities 4 on both its upper and lower surfaces, whereas the protrusions 3 and cavities 4 located on the upper surface of support layer 1 have a size different from that of the protrusions 3 and cavities 4 located on the lower side. As shown, the height of the protrusions 3 on the upper side is substantially the same as the height of the protrusions 3 on the lower side, the lateral extension of all protrusions (i.e. those located on the upper and lower surfaces) is substantially the same, and the size of the base portions 3 b of the protrusions is substantially the same. However, the longitudinal extent (i.e. the extent in the length-wise direction of the support layer 1) of the protrusions 3 located on the lower surface of support layer 1 is greater than that of the protrusions 3 located on the upper surface. Also the reverse configuration may be adopted.

With respect to the T-shape of the protrusions and cavities shown in FIG. 3, properties of the T-shape include: width (or thickness) and height of the stem, width and thickness (or height) of the horizontal portion, overall height, curvature of transition regions (e.g. between surface and base portion or between base portion and head portion). It should be understood that one or more of these aforementioned properties of the protrusions 3 (and corresponding cavities 4) on the lower and upper surfaces may vary independently.

As an example curvature of transition regions defining the lateral surfaces of the head portions may be an arch of a circle.

FIG. 4 shows an isometric view of a fourth embodiment of a support layer having L-shaped protrusions and cavities. Similar to the T-shaped protrusions 3 and cavities 4 described above, the support layer can have, on one or both surfaces, protrusions 3′ and cavities 4′ having an L-shape. The L-shaped protrusions 3′ correspond to the L-shaped cavities 4′ in a manner similar to the T-shaped protrusions 3 and cavities 4 described with respect to FIG. 1 and 1 a. The protrusions 3′ are formed side by side each other in a manner defining a cavity 4′ between two adjacent protrusions 3′ having an L-shape identical to that of the protrusions 3′. Thus, if turned upside down, the protrusions 3′ would exactly fit the cavities 4′. In other words, two identical support layers 1 having protrusions 3′ and cavities 4′ could be arranged against one another such that the protrusions of one support layer would accurately fit the cavities in the other support layer, and vice versa.

In a non-shown example, T-shaped non symmetric protrusions 3 may be adopted; in particular the stems (base portions) may be not placed exactly in the mid vertical plane, but close to one or the other side of the lateral surfaces of the corresponding head portion.

FIG. 5 illustrates a manufacturing step of a support layer such as shown in FIG. 2. In one embodiment, support layers 1′ and 1″ are formed from a single pre-product by cutting the pre-product in a particular manner. As shown in FIG. 5, the lower surface of support layer 1′ has protrusions corresponding to cavities on the upper surface of support layer 1″, and the lower surface of support layer 1′ has cavities corresponding to protrusions on the upper surface of support layer 1″.

By cutting the pre-product in a laterally straight manner along a predefined path, tracing a series of T-shapes, the protrusions and cavities are defined. It is noted, here, that the described steps are equally applicable to manufacturing steps for support layers having L-shaped protrusions and cavities. For clarity, however, the description refers to the T-shaped protrusions and cavities shown in FIG. 5 in an exemplary and non-limiting manner. As shown in FIG. 5, each “upright” T-shape, for example, corresponds to a cavity on the lower surface of the support layer 1′ and a protrusion on the upper surface of the support layer 1″, and each “inverted” (i.e. upside-down) T-shape corresponds to a protrusion on the lower surface of the support layer 1′ and a cavity on the upper surface of the support layer 1″. After cutting the pre-product in this manner, the two substantially identical support layers 1′ and 1″ may be separated from each other, for example by pulling or laterally sliding the two support layers apart.

It is noted that there is no need to dispose of any clippings or other waste material, since the cutting is effected in a manner in which no material has to be cut from either support layer 1′ and/or 1″, or from the pre-product before or after cutting. Support layers 1′ and 1″, if put together again, would essentially correspond to the initial pre-product, notwithstanding the cut that has been made. The pre-product can be, for example, a single block of material comprising foamed polyurethane or latex. The pre-product can also be a continuous band of material, for example pre-produced foamed polyurethane or latex continuously supplied by a feeding machine. The pre-product can be continuously cut while being provided by a feeding machine and can subsequently be cut into segments. Alternatively, continuously fed pre-product can be segmented into discrete blocks first, and then processed (i.e. cut as described above) into support layers.

In respect to the manufacturing process of the pre-product of latex, first, all basic components (the initial latex emulsion and gelling or coagulating agent, i.e. FSS or carbon dioxide) are mixed into a compound and then fed to a continuous foamer into which compressed gas (air—necessary to make a foam) is pumped. At the same time, a mold is cleaned and heated for subsequent filling. The mold is filled with latex foam exiting the foamer particularly until it fills the mold completely.

The mold containing the product is heated (e.g. placed in a oven) for vulcanization. Vulcanization is the process of latex hardening per share on the temperature and the presence of sulfur. Once the pre-product is ready, it is demoulded; normally the pre-product is washed and subsequently dried. A new core (pre-product) for a latex mattress is ready for control and storage and/or for the above mentioned subsequent manufacturing steps.

Polyurethane foam is manufactured from polymers. The polymers are joined by urethanes, or carbamates, and stored as a liquid in large vats. The vats are continuously agitated to keep the solution mixed and ready for production. To produce polyurethane foam, the liquid is heated and pumped into a series of pipes, where it is sprayed out onto sheets of heavy paper. Once it has been sprayed, it is infused with carbon dioxide gas, which causes it to rise. Additional sheets of paper are added to form the foam into the desired shape, and it is then cooled and cut to the desired length.

FIG. 6 shows a layered structure for a mattress comprising a support layer such as shown in FIG. 1. The layered structure 60 comprises a support layer 64, as well as a superjacent layer 62 and a subjacent layer 66. Layers 62 and 66 can be substantially continuous or, as shown in FIG. 6, have a ribbed structure. In case layers 62 and/or 66 have a ribbed structure, the individual ribs can be positioned and spaced in a manner corresponding to the positions and spacing of protrusions in the support layer 64. As shown in FIG. 6, the ribs can be in superimposition with the protrusions. It is understood that layers 62 and 66 can have any desired shape and/or structure suitable for the use in mattresses. The material of which layers 62, 64, and 66 are made can be the same or different from one another.

FIG. 7 shows a layered structure for a mattress comprising a support layer such as shown in FIG. 1, the support layer being non-planar along its length. The layered structure 70 comprises a support layer 74, as well as a superjacent layer 72 and a subjacent layer 76. Layers 72 and 76 can be substantially continuous and have at least one substantially flat or planar surface, as shown in FIG. 7. Support layer 74 can be in a non-planar state. As shown in FIG. 7, support layer 74 can be curved along its length, whereas it is substantially straight (e.g. horizontal) along its width. Layer 72 and 76 are shaped to compensate for the curvature of support layer 74, such that the overall top and bottom surfaces of layered structure 70 are substantially flat or planar. By varying the thicknesses of layers 72 and/or 76 as well as the curvature of layer 74, the flexibility or stiffness of layered structure 70 can be adjusted and varied along a length thereof.

FIG. 8 shows a layered structure for a mattress comprising a support layer such as shown in FIG. 2, comprising additional layers. The layered structure 80 comprises a support layer 84, as well as a superjacent layer 82 and a subjacent layer 86. Support layer 84 is substantially similar to the support layer 1 shown in FIG. 2. Further, layered structure 80 comprises an additional layer 85, positioned between support layer 84 and subjacent layer 86. As described above with respect to FIG. 6, layers 82, 85, and 86 can be substantially continuous or have a ribbed structure. In the embodiment shown in FIG. 8, additional layer 85 is substantially continuous, and layers 82 and 86 have a ribbed structure. Again, the individual ribs of layers 82 and 86 can be positioned and spaced in a manner corresponding to the positions and spacing of protrusions in the support layer 84. As shown in FIG. 8, the ribs can be substantially in superimposition with the protrusions. It is understood that layers 82, 85, and 86 can have any desired shape and/or structure suitable for the use in mattresses. By varying the thicknesses and structure of layers 82, 84, 85, and/or 86, the flexibility or stiffness of layered structure 80 can be adjusted. In particular, the specific properties of support layer 84, as described above, can be used to adjust the flexibility or stiffness of layered structure 80.

FIG. 9 shows an alternative layered structure for a mattress comprising a support layer such as shown in FIG. 2, where the support layer and additional layers are integrally formed. In general, the embodiment shown in FIG. 9 is substantially similar to that shown in FIG. 8. However, layers 84, 85, and 86 as described with respect to FIG. 8 are shown as an integrally formed (i.e. one-piece) layer in the embodiment shown in FIG. 9. Individual properties (e.g., thicknesses, structures, materials, etc.) can be chosen as desired, whereas in contrast to the embodiments shown in FIGS. 6 to 8, layer 94 (a single integrally formed layer substantially corresponding to layers 84, 85, and 86 as shown in FIG. 8) is formed of a single material. In general, it is understood that, as desired, individual layers (e.g. layers 84, 85, 86 in FIG. 8 or layer 94 in FIG. 9) can be made from the same or different material(s). Further, if any layers are generally made from the same material, specific material properties can vary from layer to layer, for example density, moisture absorption capabilities, or other properties.

FIG. 10 a shows a support layer such as shown in FIG. 1 comprising a longitudinal insert. Support layer 1 can be further provided with a longitudinal insert 10, as shown in FIG. 10 a, in order to modify the stiffness in a marginal region of support layer 1. Insert 10 can be used, for example, to increase the stiffness of support layer 1 on the laterally outermost regions. This effect is desired, for example, when support layer 1 is comprised in a mattress, in order to provide the mattress with more support (e.g. higher stiffness) on either side along a length thereof, while maintaining softer or more flexible characteristics along a center region thereof.

It is clear that the longitudinal insert may be present on both longitudinal side and/or on either or both lateral side (eventually forming a continuous frame on the perimeter).

FIG. 10 b shows a support layer such as shown in FIG. 1 comprising a lateral insert. Support layer 1 can, alternatively or in addition to one or more longitudinal inserts as described with respect to FIG. 10 a above, be provided with a lateral insert 11. Similar to the effect of longitudinal insert 10, lateral insert 11 can be used in order to modify the stiffness in a region of support layer 1, which is interested by lateral insert 11. As shown in FIG. 10 b, lateral insert 11 can extend over approximately 20% of the length of support layer 1, in order to increase the stiffness of support layer 1 in this region. It is noted that insert 11 can be configured to cover a larger or a smaller region of support layer 1, for example 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, or 90%. Likewise, insert 11 can be positioned anywhere along the length of support layer 1, as desired. The coupling of the insert to the support layer being defined by an interaction of the protrusions of the insert and the cavities of the support layer provide for discrete positioning of the insert with respect to the support layer (e.g., the insert can be discretely shifted by the distance between two adjacent cavities). Further, one or more inserts 11 can be positioned along support layer 1, either adjacent to one another or spaced apart from one another, in order to achieve a desired distribution of flexibility and/or stiffness in specific regions of support layer 1. Still further, if one or more inserts 11 are combined with one or more longitudinal inserts 10, a lateral extent of insert(s) 11 can be adjusted depending upon the dimensions and/or position of insert(s) 10, so as to fill the available space (e.g., the space left between two longitudinal inserts 10). It is understood that inserts 11 can interest the full width w of support layer 1 or only a portion thereof. For example, an insert having a width of 50% or 75% of the width w of support layer 1 can be used. Generally, inserts having a width of 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90%, or 100% of the width w of support layer 1 can be used. In case an insert 11 interesting only a portion of the full width of support layer 1 is used, the insert 11 can be positioned substantially on a central longitudinal axis of support, or be placed in a position shifted to either side thereof. Using one or more inserts 10 and/or 11, the individual characteristics (e.g., flexibility, stiffness, etc.) of the support layer 1 can be modified and adjusted.

Of course the insert 11 may be a single insert, meaning that a single cavity receives the insert for its full or partial lateral extension.

Inserts have been shown on the upper side only, but normally can be placed on either or both sides.

FIG. 11 shows a support layer such as shown in FIG. 1 comprising two longitudinal inserts defining a lateral margin. In general, inserts 12 a and 12 b provide substantially the same functionality like longitudinal inserts 10 as described above. Further, inserts 12 a and 12 b can be used to define a lateral margin as shown in FIG. 11, defining a space there between. The space defined in this way can be used to position and contain one or more additional components with respect to the support layer 1 and the margin defined by inserts 12 a and 12 b. Additional components include, but are not limited to, filling material, inserts, additional layers, and the likes.

It is to be noted that further inserts may be adopted also on lateral sides to define a complete frame on all four sides.

In general, inserts 10, 11, 12 a, and 12 b can comprise any of the following materials: foamed latex, flexible foamed polyurethane, “slow-memory” polyurethane foam, and “slow-memory” viscoelastic polyurethane foam. Inserts can be made from other suitable materials, too.

Generally, inserts 10, 11, 12 a, and 12 b comprise protrusions and cavities corresponding to those present in the support layer 1, which the inserts are intended to be placed on. This way, the inserts are provided with a simple, cost-effective, and easy-to-use fastening mechanism that can be easily integrated into manufacturing of mattresses. Inserts are held in place by friction-fit between corresponding cavities and protrusions. Alternative or additional fastening means can be employed, for example adhesives or heat bonding. It is understood that inserts 10, 11, 12 a, and 12 b can interact (e.g., be placed on) any of the surfaces of support layer 1. For example, inserts may be placed on the upper surface of support layer 1 and/or the lower surface of support layer 1.

In general, insert 1 may comprise (or be completely made and constituted by) any of the following materials: foamed latex, flexible foamed polyurethane, “slow-memory” polyurethane foam, and “slow-memory” viscoelastic polyurethane foam.

Insert 1 may be made from other suitable flexible material, too.

As to further inserts to be coupled to the mattress insert 1, it is to be noted that since this further inserts are simply coupled in a removable manner (i.e. no glue or adhesives are generally used), the mattress may be personalized at any time in different ways.

Moreover the further inserts, particularly those of FIG. 11, may also have internal (lateral and/or longitudinal) cavities to vary stiffness.

Furthermore the further inserts, particularly those of FIG. 11, may also have inner sloped sides to help accommodating other elements over the insert and inside the frame defined by the further inserts.

While the invention has been described in connection with what is presently considered to be the most practical and preferred embodiments, it is to be understood that the invention is not to be limited to the disclosed embodiments, but on the contrary, is intended to cover various modifications and equivalent arrangements included within the spirit and the scope of the appended claims. 

1. A support layer for a mattress, comprising: a first surface and a second surface, the second surface being disposed opposite the first surface; wherein the first surface comprises a plurality of protrusions extending laterally to a length of the support layer, the protrusions defining a plurality of cavities extending laterally to the length of the support layer, wherein the shape of the protrusions matches the shape of the cavities when the support layer is in a substantially planar state, and wherein the protrusions and cavities each have a base portion and a head portion, the head portion defining an undercut.
 2. The support layer according to claim 1, wherein the base portion has a first width and the head portion has a second width, the first width being less than the second width.
 3. The support layer according to claim 1, wherein the protrusions and cavities are symmetrical with respect to a vertical plane extending through the corresponding base portion, the vertical plane extending laterally to the length of the support layer and being substantially perpendicular thereto.
 4. The support layer according to claim 1, wherein the head portion is substantially flat.
 5. The support layer according to claim 1, wherein the protrusions and cavities have either a T-shape or an L-shape.
 6. The support layer according to claim 1, wherein the shape of the protrusions is configured to provide, upon deformation of the support layer along its length, a first stiffness when adjacent protrusions to not contact each other and a second stiffness when adjacent protrusions do contact each other.
 7. The support layer according to claim 6, wherein the first stiffness is less than the second stiffness.
 8. The support layer according to claim 1, wherein the support layer is made from a flexible material.
 9. The support layer according to claim 1, wherein the support layer is made from a material selected from the group consisting of polyurethane and latex.
 10. The support layer according to claim 1, wherein the plurality of protrusions and cavities are comprised in the first and second surfaces.
 11. The support layer according to claim 10, wherein the protrusions and cavities in the first surface have a size different from the protrusions and cavities in the second surface.
 12. The support layer according to claim 9, wherein the support layer is symmetrical with respect to a mid plane extending through the support layer, the mid plane being substantially parallel to the support layer.
 13. The support layer according to claim 1, wherein the second surface is substantially flat.
 14. A support layer for a mattress, comprising: an upper surface and a lower surface, the lower surface being disposed opposite the upper surface; wherein the upper and lower surfaces comprise a plurality of protrusions extending laterally with respect to a length of the support layer, the protrusions defining a plurality of cavities extending laterally with respect to the length of the support layer, wherein the protrusions and cavities each have a respective base portion and a respective head portion, the respective head portions being flat and defining an undercut, the protrusions having a T-shape, and wherein the support layer is made from a flexible material.
 15. The support layer according to claim 14, wherein the shape of the protrusions matches the shape of the cavities when the support layer is in a substantially planar state.
 16. A mattress comprising at least one support layer having a first surface and a second surface, the second surface being disposed opposite the first surface; wherein the first surface comprises a plurality of protrusions extending laterally to a length of the support layer, the protrusions defining a plurality of cavities extending laterally to the length of the support layer, wherein the shape of the protrusions matches the shape of the cavities when the support layer is in a substantially planar state, and wherein the protrusions and cavities each have a base portion and a head portion, the head portion defining an undercut.
 17. The mattress according to claim 16, further comprising a lateral insert, the lateral insert comprising protrusions and cavities matching those of the support layer, the lateral insert extending along substantially a width of the support layer and being configured to increase a stiffness of the support layer in an area interested by the lateral insert.
 18. The mattress according to claim 16, further comprising a longitudinal insert, the longitudinal insert comprising protrusions and cavities matching those of the support layer, the longitudinal insert extending along substantially the length of the support layer and being configured to increase a stiffness of the support layer in an area interested by the longitudinal insert.
 19. A mattress comprising at least one support layer an upper surface and a lower surface, the lower surface being disposed opposite the upper surface; wherein the upper and lower surfaces comprise a plurality of protrusions extending laterally with respect to a length of the support layer, the protrusions defining a plurality of cavities extending laterally with respect to the length of the support layer, wherein the protrusions and cavities each have a respective base portion and a respective head portion, the respective head portions being flat and defining an undercut, the protrusions having a T-shape, the support layer being made from a flexible material, wherein the support layer is positioned between a superjacent layer and a subjacent layer, the superjacent layer having a substantially flat bottom surface and the subjacent layer having a substantially flat top surface, and wherein the support layer is non-planar along its length, the support layer being curved along its length and straight along its width.
 20. The mattress according to claim 19, wherein the bottom surface of the superjacent layer and/or the top surface of the subjacent layer are in contact with the support layer and further comprising an upper padding layer and/or a lower padding layer, the upper and lower padding layers comprising cotton, wool, linen, silk, camel-hair, or combinations thereof, and wherein the mattress further comprises an external cover being a textile cover enclosing the entire mattress and layers comprised therein. 